JP2020200886A - Pipe joint and its manufacturing method - Google Patents

Abstract

To provide a pipe joint which is easy in manufacturing, suppressed in the displacement and exfoliation of an elastic body, and can sufficiently exert a water intrusion suppression effect to a foaming resin layer from an end face of a heat insulation pipe, and its manufacturing method.SOLUTION: A pipe joint 1 comprises a pipe main body part 10 having a foaming resin layer 40, cylindrical socket parts 20a, 20b surrounding opening parts 12a, 12b of the pipe main body part 10, and annular elastic bodies 30a, 30b. Steps 24a, 24b are formed in a boundary portion between the socket parts 20a, 20b and the pipe main body part 10, faces of the steps 24a, 24b at opening ends 21a, 21b are reception faces 25a, 25b, outside diameters of the elastic bodies 30a, 30b are equal to inside diameters of the socket parts 20a, 20b or smaller, the elastic bodies 30a, 30b adhere to the reception faces 25a, 25b via adhesion layers 26a, 26b, and the peal strength of the reception faces 25a, 25b and the elastic bodies 30a, 30b is equal to 1 N/25 mm or higher.SELECTED DRAWING: Figure 2

Description

The present invention relates to a pipe joint and a method for manufacturing the same.

As pipes used for drainage of buildings, heat insulating pipes and pipe joints provided with a foamed resin layer as a heat insulating layer are widely used. The pipe joint is provided with a receiving portion into which the end portion of the heat insulating pipe is inserted, and a stopper formed of a step protruding inward from the inner surface is provided at the back of the receiving portion. As a connection structure between the heat insulating pipe and the pipe joint, a structure is known in which an adhesive is applied to the outer peripheral surface of the end portion of the heat insulating pipe and inserted to the position of a stopper in the receiving portion of the pipe joint to connect.

However, since the foamed resin layer is exposed on the end face of the heat insulating pipe, water easily infiltrates into the foamed resin layer from the end face of the heat insulating pipe in this connection structure, and the heat insulating effect tends to decrease. Therefore, Patent Document 1 uses a pipe joint in which an annular elastic body that does not allow water to permeate is adhered to the opening end side of the stopper via an adhesive layer, and the end face of the heat insulating tube inserted into the receiving portion is pressed against the elastic body. , A connection structure has been proposed in which elastic bodies are connected in a compressed state.

Japanese Unexamined Patent Publication No. 9-184583

However, in the pipe joint of Patent Document 1, when the elastic body is adhered to the stopper, the adhesive tends to adhere to an unexpected portion in the receiving portion, or the elastic body tends to bend. When the adhesive is unexpectedly adhered or the elastic body is bent, the adhesive position of the elastic body is displaced or the elastic body is insufficiently adhered, resulting in a problem that the elastic body adheres to the foamed resin layer of the heat insulating tube. The effect of suppressing the infiltration of water is less likely to be exhibited. Since it is difficult to peel off and re-bond the elastic body once adhered, a high degree of precision is required for adhering the elastic body, and the production is complicated. Further, if the adhesive layer is weakly adhered and the elastic body is easily peeled off, the elastic body may be peeled off at the time of market distribution of the pipe joint.

The present invention provides a pipe joint which is easy to manufacture, suppresses displacement and peeling of an elastic body, and can sufficiently exhibit an effect of suppressing water infiltration from the end face of a heat insulating pipe into a foamed resin layer, and a method for manufacturing the same. The purpose is.

The present invention has the following aspects.
[1] A pipe joint including a pipe body portion provided with a heat insulating layer, a tubular receiving portion surrounding an opening of the pipe body portion, and an annular elastic body.
An annular step protruding inward from the inner surface of the receiving portion is formed at the boundary portion between the receiving portion and the pipe main body portion.
The surface of the step facing the opening end of the receiving portion is a receiving surface for receiving the pipe inserted into the receiving portion.
The outer diameter of the elastic body is equal to or less than the inner diameter of the socket.
The elastic body is adhered to the receiving surface via an adhesive layer,
A pipe joint in which the peel strength between the receiving surface and the elastic body is 1 N / 25 mm or more.
[2] The pipe joint according to [1], wherein the inner diameter of the elastic body is equal to or larger than the inner diameter of the step.
[3] The pipe joint according to [1] or [2], wherein the thickness of the elastic body is 2 mm or more and 15 mm or less.
[4] The shape of the cross section of the elastic body in the thickness direction is rectangular.
The pipe joint according to any one of [1] to [3], wherein the adhesive layer is provided only on the surface of the elastic body facing the receiving surface.
[5] The method for manufacturing a pipe joint according to any one of [1] to [4].
After providing an adhesive layer on one surface of the elastic sheet, they are punched out in an annular shape to form the annular elastic body having the adhesive layer, and the elastic body is adhered to the receiving surface via the adhesive layer. , Manufacturing method of pipe joints.
[6] The method for manufacturing a pipe joint according to any one of [1] to [4].
A method for manufacturing a pipe joint, in which the adhesive layer is provided on the receiving surface, and then the elastic body is adhered to the receiving surface via the adhesive layer.

According to the present invention, a pipe joint that is easy to manufacture, suppresses displacement and peeling of an elastic body, and can sufficiently exhibit the effect of suppressing water from entering the foamed resin layer from the end face of the heat insulating pipe, and a method for manufacturing the pipe joint. Can be provided.

It is a side view which shows the pipe joint which concerns on one Embodiment of this invention. It is a vertical sectional view of the pipe joint of FIG. It is an enlarged view of the receiving part of the pipe joint of FIG. It is sectional drawing which showed the state which the insulation pipe was inserted into the receiving part of the pipe joint of FIG. It is sectional drawing which shows the pipe joint which concerns on another embodiment of this invention.

[First Embodiment]
(Pipe fitting)
Hereinafter, the pipe joint according to the embodiment of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 3, the pipe joint 1 of the present embodiment is a joint used for connecting a drain pipe or the like (an L-shaped pipe joint joint generally called an “elbow”). This is an example. The pipe joint 1 of the present embodiment includes a pipe body portion 10, two receiving portions 20a and 20b, and two elastic bodies 30a and 30b.

The pipe body 10 is cylindrical, bent in an L shape, and has a curved flow path inside. An opening 12a is formed at the first end 10a of the pipe body 10, and an opening 12b is formed at the second end 10b.

The receiving portion 20a has a cylindrical shape and extends from the first end portion 10a of the pipe main body portion 10 so as to surround the opening portion 12a of the pipe main body portion 10. The receiving portion 20b has a cylindrical shape and extends from the second end portion 10b of the pipe main body portion 10 so as to surround the opening 11b of the pipe main body portion 10. The tube main body portion 10, the receiving portion 20a, and the receiving portion 20b are integrally formed.

An annular step 24a protruding inward from the inner surface 22a of the receiving portion 20a is formed at the boundary portion between the receiving portion 20a and the first end portion 10a of the pipe main body portion 10. The surface of the step 24a facing the opening end 21a of the receiving portion 20a is a receiving surface 25a for receiving the pipe inserted into the receiving portion 20a, a so-called stopper.

Similarly, at the boundary portion between the receiving portion 20b and the second end portion 10b of the pipe main body portion 10, an annular step 24b protruding inward from the inner surface 22b of the receiving portion 20b is formed. The surface of the step 24b facing the opening end 21b of the receiving portion 20b is a receiving surface 25b for receiving the pipe inserted into the receiving portion 20b, that is, a so-called stopper.

The receiving surfaces 25a and 25b of the present embodiment are formed at the boundary portion between the tube main body portion 10 and the receiving portion 20a and the receiving portion 20b over the entire circumference in the circumferential direction, respectively, as viewed from the opening end side. The front view shape is an annular shape. The ring shape of the receiving surfaces 25a and 25b in front view is not limited to a circle, and may be an ellipse, a polygon, or the like.

The heights of the receiving surfaces 25a and 25b of the steps 24a and 24b may be within a range in which the ends of the heat insulating pipe to be inserted can be received, and are set to, for example, the same as the thickness of the heat insulating pipe to be inserted. ..

The inner diameter of the receiving portion 20a and the outer diameter of the heat insulating pipe are not particularly limited, but the larger the outer diameter of the heat insulating pipe, the easier it is for the heat insulating pipe to be cut at an angle from the plane orthogonal to the pipe axis. , The distance between the end surface of the heat insulating pipe and the receiving surface 25a tends to be uneven. Therefore, the larger the inner diameter of the receiving portion 20a and the outer diameter of the heat insulating pipe, the easier it is to obtain the water blocking effect and the heat insulating effect by the elastic body. Specifically, the inner diameter of the receiving portion 20a or the outer diameter of the heat insulating pipe, which tends to obtain a water blocking effect and a heat insulating effect, is 60 mm or more, 75 mm or more is more likely to be obtained, and 88 mm or more is further effective. Cheap.

The tube body 10 includes a cylindrical foamed resin layer 40 and a non-foamed resin layer 50 that covers the entire inner and outer surfaces of the foamed resin layer 40. The receiving portion 20a and the receiving portion 20b are formed of a non-foamed resin layer 50. A part of the foamed resin layer 40 on the receiving portion 20a side bites into the non-foamed resin layer 50 of the receiving portion 20a. Further, a part of the foamed resin layer 40 on the receiving portion 20b side bites into the non-foamed resin layer 50 of the receiving portion 20b. The foamed resin layer does not have to bite into the receiving portion.

The foamed resin layer 40 is a layer formed by foaming a foamable resin composition and functions as a heat insulating layer.
The foaming ratio of the foamed resin layer 40 is preferably 1.0 times or more and 8.0 times or less, more preferably 1.1 times or more and 5.0 times or less, and further preferably 1.2 times or more and 3.0 times or less. When the foaming ratio is within the above numerical range, the heat insulating performance is excellent. The expansion ratio can be adjusted according to the type or amount of resin, the type or amount of foaming agent, manufacturing conditions, and the like.

The foaming ratio can be measured by the following method.
A portion of the tube body 10 having a circumferential direction of 10 mm or more and an axial direction of 50 mm is cut out, the non-foamed resin layer 50 is cut, and only the foamed resin layer 40 is processed into a plate shape having a length of about 50 mm. To do. In addition, four test pieces are prepared centering on the points divided into four evenly in the circumferential direction.
According to JIS K 7122, the apparent density of the test piece is obtained up to 3 digits after the decimal point using a water substitution type specific gravity measuring device at 23 ° C. ± 2 ° C., and the foaming magnification is calculated by the following formula (1).
m = γc / γ ・ ・ ・ (1)
(In the formula (1), m is the foaming magnification, γ is the apparent density of the foamed resin layer (g / cm ³ ), and γc is the density of the foamed resin layer when not foamed (g / cm ³ ). The density of the foamed resin layer when it is not foamed can be measured from the melted foamed resin layer.)

In the foamed resin layer 40, a plurality of bubbles are formed, substantially no pores are present in the bubble wall, and at least a part of the plurality of bubbles is closed cells that are not communicated with each other. ..
The closed cell ratio of the foamed resin layer 40 is preferably 85% or more, more preferably 90% or more. The upper limit is not particularly limited, but is substantially 99% or less. When the closed cell ratio of the foamed resin layer 40 is within the above numerical range, low thermal conductivity can be maintained for a long period of time, and the heat insulating property is more excellent.
The closed cell ratio is measured according to JIS K 7138: 2006.

Examples of the foamable resin composition include a composition containing a resin and a foaming agent.
Specific examples of the resin include polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-ethylenepropylene diene-styrene copolymer (AES resin), and acrylonitrile-acrylic rubber-styrene copolymer (AAS). Resin), polyethylene, polypropylene, acrylic resin and the like. Of these, polyvinyl chloride and ABS resin are preferable.
As the resin, only one type may be used, or two or more types may be used in combination.

As the foaming agent, either a volatile foaming agent or a decomposition type foaming agent may be used.
Examples of the volatile foaming agent include aliphatic hydrocarbons (propane, butane, pentane, etc.), alicyclic hydrocarbons (cyclopentane, cyclohexane, etc.), halogenated hydrocarbons (trichlorofluoromethane, etc.), ethers (trichlorofluoromethane, etc.). Dimethyl ether, diethyl ether, etc.), ketones (acetone, methyl ethyl ketone, etc.) and the like.

Examples of the decomposable foaming agent include inorganic foaming agents such as sodium bicarbonate (sodium hydrogen carbonate), sodium carbonate, ammonium bicarbonate, ammonium nitrite, azide compound, and sodium borohydride, azodicarboxylic amide, and barium azodicarboxylic acid. , Dinitrosopentamethylenetetramine and other organic foaming agents.
In addition, a gas such as carbon dioxide, nitrogen, or air may be used as the foaming agent.

As the foaming agent, a decomposition type foaming agent is preferable from the viewpoint of excellent foaming performance, and among them, baking soda and azodicarbonamide are more preferable. As the foaming agent, only one type may be used, or two or more types may be used in combination.
The content of the foaming agent in the foamable resin composition is preferably 0.1 part by mass or more and 8 parts by mass or less, more preferably 1 part by mass or more and 5 parts by mass or less, with respect to 100 parts by mass of the resin. It is more preferably 3 parts by mass or less.

The foamable resin composition may contain components (arbitrary components) other than the resin and the foaming agent as long as the effects of the present invention are not impaired. Examples of the optional component include a colorant, a flame retardant, an antioxidant, an ultraviolet absorber, a light stabilizer and the like.
The content of the optional component in the foamable resin composition is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 20 parts by mass or less with respect to 100 parts by mass of the resin.

The non-foaming resin layer 50 is a layer formed by molding a non-foaming resin composition. Since the pipe joint 1 has the non-foamed resin layer 50, the strength of the pipe joint 1 is increased. The non-foamed resin layer 50 is preferably transparent.

Examples of the non-foamable resin composition include compositions containing a resin.
Examples of the resin include the same resins as those mentioned in the foamable resin composition, and polyvinyl chloride and ABS resins are preferable. As the resin, only one type may be used, or two or more types may be used in combination.

The non-foamable resin composition may contain components (arbitrary components) other than the resin as long as the effects of the present invention are not impaired. Examples of the optional component include a colorant, a flame retardant, an antioxidant, an ultraviolet absorber, a light stabilizer and the like.
The content of the optional component in the non-foamable resin composition is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 20 parts by mass or less with respect to 100 parts by mass of the resin.

The non-foamable resin composition does not need to contain a foaming agent, but may contain a foaming agent. The amount of the foaming agent contained in the non-foamable resin composition is preferably 0 parts by mass or more and 8 parts by mass or less, more preferably 0 parts by mass or more and 5 parts by mass or less, and 0 parts by mass or more with respect to 100 parts by mass of the resin. More preferably, it is 3 parts by mass or less.
The foaming ratio of the non-foamed resin layer is preferably 0 times, but those having low foaming at 1.5 times or less are not excluded from the present invention.

The elastic body 30a is an annular elastic body. The elastic body 30a is adhered to the receiving surface 25a in the receiving portion 20a via the adhesive layer 26a. Further, the center of the annular elastic body 30a is adhered so as to be the same as the center of the receiving portion 20a.
The front view shape of the elastic body 30a seen from the opening end 21a side of the receiving portion 20a is preferably similar to the ring shape of the receiving surface 25a in the front view, and is preferably an annular shape. The front view shape of the elastic body 30a may be different from the front view shape of the receiving surface 25a, or may be an ellipse, a polygon, or the like.

In the present embodiment, the shape of the cross section of the elastic body 30a in the thickness direction is rectangular, and the adhesive layer 26a is provided only on the surface of the elastic body 30a facing the receiving surface 25a. As a result, when the elastic body 30a is adhered to the receiving surface 25a, the adhesive layer 26a is less likely to adhere to the inner surface 22a of the receiving portion 20a, and the elastic body 30a can be adhered without being displaced from the receiving surface 25a. Further, since the adhesive layer 26a is not formed on the side surface of the elastic body 30a, the elastic body 30a is not adhered to the inner surface of the receiving portion 20a and can be compressed in the insertion direction of the heat insulating pipe, so that the water blocking effect is obtained. Easy to obtain.
The elastic body 30a having a rectangular cross section can be obtained, for example, by punching an elastic sheet in an annular shape.
The shape of the cross section of the elastic body 30a in the thickness direction is not limited to a rectangular shape, and may be a circular shape, an elliptical shape, a polygonal shape, or the like.

The thickness of the elastic body 30a is preferably 2 mm or more and 15 mm or less, more preferably 4 mm or more and 12 mm or less, and further preferably 6 mm or more and 10 mm or less. When the thickness of the elastic body 30a is equal to or more than the lower limit, the elastic body 30a maintains an appropriate rigidity and is hard to bend. In particular, even when the outer diameter of the elastic body 30a is large, for example, 60 mm or more, it is hard to bend and easy to hold. , Easy to attach to the receiving surface 25a. In addition, since a gap is unlikely to occur between the end face of the heat insulating pipe and the elastic body, a water blocking effect can be easily obtained. When the thickness of the elastic body 30a is not more than the upper limit value, the length of the receiving portion 20a can be shortened and the strength of the receiving portion 20a can be maintained.

The outer diameter of the elastic body 30a is equal to or less than the inner diameter of the receiving portion 20a. That is, as shown in FIG. 3, when the inner diameter of the receiving portion 20a is d1 and the outer diameter of the elastic body 30a is d2, d2 ≦ d1. In the present invention, it is preferable that the outer diameter of the elastic body 30a is less than the inner diameter of the receiving portion 20a, that is, d2 <d1.
When the outer diameter of the elastic body 30a and the inner diameter of the receiving portion 20a have the above-mentioned relationship, it becomes easy to insert the elastic body 30a into the receiving portion 20a and adhere it to the receiving surface 25a. Further, when the elastic body 30a is adhered to the receiving surface 25a, it is possible to prevent the adhesive from adhering to an unexpected portion in the receiving portion 20a or the elastic body 30a from bending, and the elastic body 30a is adhered. It is also possible to prevent the position from shifting. Therefore, the effect of suppressing the infiltration of water into the foamed resin layer of the heat insulating tube by the elastic body 30a can be sufficiently obtained.

The "outer diameter of the elastic body" refers to the diameter of the outer edge when the outer edge shape of the elastic body is a circle, and refers to the diameter of the circumscribed circle of the outer edge when the outer edge shape is other than a circle. Further, the "inner diameter of the receiving portion" refers to the diameter of the inner edge when the inner edge shape of the cross section perpendicular to the axial direction of the tubular receiving portion is a circle, and when it is other than a circle, the inner edge of the inner edge. Refers to the diameter of the circumscribed circle.

In the present invention, from the viewpoint that a heat insulating tube or an elastic body can be easily inserted, as in the present embodiment, a taper that gradually increases in diameter from the boundary with the receiving surface of the step toward the opening end is provided on the inner surface of the receiving portion. It is preferable that it is attached. The inner surface of the receiving portion may not have a taper.
When the inner surface of the receiving portion has a taper that gradually increases in diameter from the boundary with the receiving surface of the step toward the opening end, the outer diameter of the elastic body is the inner diameter of the receiving portion on the opening end side of the boundary. It is preferably less than. In this case, the difference between the inner diameter of the boundary between the inner surface of the receiving portion and the receiving surface of the step (the outer diameter of the receiving surface of the step) and the outer diameter of the elastic body may be 0 mm.

The difference d1-d2 between the inner diameter d1 of the receiving portion 20a and the outer diameter d2 of the elastic body 30a is preferably 0 mm or more and 4 mm or less, and more preferably larger than 0 mm and 2 mm or less. When the difference d1-d2 is equal to or greater than the lower limit value, the elastic body 30a can be easily inserted into the receiving portion 20a, and it is easy to prevent the elastic body 30a from being displaced. When the difference d1-d2 is equal to or less than the upper limit value, the central axes of the receiving portion 20a and the elastic body 30a can be easily aligned, the end face of the heat insulating layer of the heat insulating pipe is not easily exposed, and the water stopping effect is high.

The inner diameter of the elastic body 30a is preferably equal to or larger than the inner diameter of the step 24a. That is, as shown in FIG. 3, when the inner diameter of the elastic body 30a is d3 and the inner diameter of the step 24a is d4, it is preferable that d3 ≧ d4. As a result, the flow of the fluid at the connecting portion between the pipe joint and the heat insulating pipe is less likely to be obstructed by the elastic body 30a.

The difference d3-d4 between the inner diameter d3 of the elastic body 30a and the inner diameter d4 of the step 24a is preferably 0 mm or more and 4 mm or less, more preferably 0 mm or more and 2 mm or less, and may be substantially 0 mm. When the difference d3-d4 is within the above numerical range, even if the elastic body is crushed by the heat insulating pipe, the elastic body is unlikely to protrude into the water passage portion, and the fluid flow at the connecting portion between the pipe joint and the heat insulating pipe is not easily obstructed.

The peel strength of the receiving surface 25a and the elastic body 30a is 1N / 25mm or more, preferably 5N / 25mm or more, more preferably 15N / 25mm or more, still more preferably 25N / 25mm or more. When the peel strength is equal to or higher than the lower limit, peeling of the elastic body 30a due to vibration or impact during transportation of the pipe joint, contraction of the heat insulating pipe connected to the pipe joint, etc. is suppressed, and the elastic body 30a stops water. The effect is fully obtained. The upper limit of the peel strength is not particularly limited. The peel strength of the receiving surface 25a and the elastic body 30a is preferably equal to or higher than the strength of the elastic body 30a.
The "peel strength" in the present invention refers to the peel strength in an aged state after adhering the elastic body to the receiving surface. Aging is performed by storing at least 20 ° C. or higher and 40 ° C. or lower for 2 days or longer.

The peel strength of the receiving surface 25a and the elastic body 30a is measured by the following method.
The receiving portion 20a is cut perpendicularly in the axial direction along the surface of the elastic body 30a on the opening end 21a side (cutting position X in FIG. 3), and the pipe body portion 10 is vertically perpendicular to the axial direction so as to include the step 24a. (Cut position Y in FIG. 3) to obtain an annular cut piece with an exposed surface of the elastic body 30a. With the surface of the elastic body 30a of the cut piece viewed from the front, the cut piece is divided into four equal parts at equal angles (90 degrees each) around the central axis to prepare a measurement sample. The non-foamed resin layer 50 having a step 24 is cut at the peripheral end of the measurement sample to expose the adhesive surface of the elastic body 30a. The exposed part of the elastic body 30a at the end of the measurement sample is gripped with a jig, and a tensile tester is passed through a load cell under the conditions of a peeling angle of 180 degrees and a tensile speed of 300 mm / min in an atmosphere of 23 ° C. and 65% RH. The jig is pulled to perform a peeling test of the measurement sample. The average value of the measured peel strength recorded in the load cell from the start to the end is divided by the width (mm) of the elastic body 30a of the measurement sample and multiplied by 25 to convert it to a value of 25 mm width, which is used as the measurement result. ..
The above operation is performed for three samples, and the average value of the three measurement results is taken as the peel strength.

Like the elastic body 30a, the elastic body 30b is an annular elastic body, and is adhered to the receiving surface 25b in the receiving portion 20b via the adhesive layer 26b. The elastic body 30b has the same embodiment as the elastic body 30a, and the preferred embodiment is also the same.

The outer diameter of the elastic body 30b is equal to or less than the inner diameter of the receiving portion 20b. Therefore, when the elastic body 30b is adhered to the receiving surface 25b, the adhesive is unlikely to adhere to an unexpected portion in the receiving portion 20b or the elastic body 30b is less likely to bend, and the adhesive position of the elastic body 30b shifts. Can be suppressed.

The preferable range of the difference between the inner diameter of the receiving portion 20b and the outer diameter of the elastic body 30b is the same as the preferable range of the difference d1-d2. The difference between the inner diameter of the receiving portion 20b and the outer diameter of the elastic body 30b may be the same as or different from the difference d1-d2.

The inner diameter of the elastic body 30b is preferably equal to or larger than the inner diameter of the step 24b. The preferable range of the difference between the inner diameter of the elastic body 30b and the inner diameter of the step 24b is the same as the preferable range of the difference d3-d4. The difference between the inner diameter of the elastic body 30b and the inner diameter of the step 24b may be the same as or different from the difference d3-d4.

The preferable range of the peel strength of the receiving surface 25b and the elastic body 30b is the same as the preferable range of the peel strength of the receiving surface 25a and the elastic body 30a. The peel strength of the receiving surface 25b and the elastic body 30b is preferably equal to or higher than the strength of the elastic body 30b.

The elastic body 30a and the elastic body 30b are made of a resin elastic body. The elastic body 30a and the elastic body 30b may be provided with a skin layer on the surface layer.
Examples of the resin used for the elastic body 30a and the elastic body 30b include olefin resins such as polyethylene and polypropylene, and rubbers such as chloroprene rubber and ethylene propylene diene rubber (EPDM). As the resin, only one type may be used, or two or more types may be used in combination.

As the resin elastic body constituting the elastic body 30a and the elastic body 30b, a plurality of bubbles are formed, and there are substantially no holes in the bubble wall, and the closed cells in which the plurality of bubbles do not communicate with each other are formed. The resin foam having is preferable.

The closed cell ratio of the resin foams constituting the elastic body 30a and the elastic body 30b is preferably 30% or more, more preferably 50% or more. The upper limit is not particularly limited, but is substantially 99% or less. When the closed cell ratio of the elastic body 30a is within the above numerical range, it is possible to suppress the infiltration of water into the foamed resin layer of the heat insulating pipe inserted into the receiving portion of the pipe joint.

The foaming ratio of the resin foam is preferably 1.1 times or more and 50 times or less, more preferably 5.0 times or more and 45 times or less, and further preferably 10 times or more and 40 times or less. When the foaming ratio is at least the lower limit value, dew condensation can be prevented from occurring on the outer surface of the receiving portion 20a at the portion where the elastic body 30a is installed because the heat insulating property is excellent. In addition, it has excellent flexibility, and it is easy to obtain a water blocking effect because a gap is unlikely to occur between the end face of the heat insulating pipe and the elastic body. When the foaming ratio is not more than the upper limit value, the elastic body 30a maintains an appropriate rigidity, is hard to bend, and is easy to hold, so that it can be easily attached to the receiving surface 25a. The expansion ratio can be adjusted according to the type or amount of resin, the type or amount of foaming agent, manufacturing conditions, and the like.

The foaming ratio of the resin foams constituting the elastic body 30a and the elastic body 30b is determined by cutting the resin foam together with the adhesive layer from the pipe joint and then cutting the adhesive layer from the resin foam as a test piece. It can be measured in the same manner as the foaming ratio of 40.

The elastic body 30a and the elastic body 30b may contain components (arbitrary components) other than the resin and the foaming agent as long as the effects of the present invention are not impaired. Examples of the optional component include a colorant, a flame retardant, an antioxidant, an ultraviolet absorber, a light stabilizer and the like.

The thickness of the adhesive layer 26a is preferably 0.005 μm or more and 4 μm or less, and more preferably 0.1 μm or more and 2 μm or less. When the thickness of the adhesive layer 26a is within the above numerical range, the peel strength of the receiving surface 25a and the elastic body 30a is sufficiently high.
The preferable range of the thickness of the adhesive layer 26b is the same as the preferable range of the thickness of the adhesive layer 26a.
When the adhesive layer 26a is formed by applying a liquid pressure-sensitive adhesive or a liquid adhesive, it may be applied so that the coating amount of the pressure-sensitive adhesive or the adhesive component is 5 to 300 g / m ^{2. 2} is more preferable. It should be noted that this coating amount is after volatilization of volatile components such as a solvent.

The adhesive layer 26a and the adhesive layer 26b include, for example, a liquid adhesive in which a pressure-sensitive adhesive is dissolved or dispersed in a solvent, or a solvent-volatile, reaction-curable, or thermosetting liquid adhesive on an elastic body or a receiving surface. Examples thereof include a layer formed by coating. The viscosity of the liquid pressure-sensitive adhesive or the liquid adhesive at 20 ° C. is preferably 300 mPa · s or more and 15,000 mPa · s or less, and more preferably 1000 mPa · s or more and 10,000 mPa · s or less. If the viscosity is in this range, it is possible to prevent the adhesive or the adhesive from adhering to the inner surface of the receiving portion 20a due to dripping. Further, the adhesive layer 26a and the adhesive layer 26b may be formed of a double-sided tape provided with an adhesive on both sides of the base material, and in this case as well, the adhesive or the adhesive adheres to the inner surface of the receiving portion 20a. Can be prevented. Among them, when the non-foamed resin layer 50 of the pipe joint 1 is made of ABS resin, the resistance to the solvent is low, so that the adhesive is dissolved or dispersed in a small amount of solvent and applied to the elastic body in advance. Dried and dried, or double-sided tape is preferable.

The pressure-sensitive adhesive is not particularly limited, and for example, natural rubber, styrene / butadiene latex-based pressure-sensitive adhesive, polyisobutylene, polyisobutylene, butyl rubber, and thermoplastic rubber ABA block polymer (where A is a thermoplastic polystyrene block and B is (Representing polyisobutylene, polybutadiene, polyethylene, polybutylene block), acrylic adhesives, silicone adhesives and other adhesives can be mentioned. The main component of the acrylic pressure-sensitive adhesive is a copolymer of (meth) acrylic acid and (meth) acrylic acid ester, and any (meth) acrylic acid ester can be used. The (meth) acrylic acid represents acrylic acid and methacrylic acid. As the pressure-sensitive adhesive, only one type may be used, or two or more types may be used in combination.

As shown in FIG. 4, in the pipe joint 1, a heat insulating pipe 100 provided with non-foamed resin layers 120 on the inner surface side and the outer surface side of the foamed resin layer (heat insulating layer) 110 is inserted into the receiving portion 20a. The heat insulating tube 100 can be connected in a compressed state by pressing it against the elastic body 30a. As a result, the elastic body 30a suppresses the infiltration of water into the foamed resin layer 110 of the heat insulating pipe 100. Similarly, another heat insulating tube 100 is inserted into the receiving portion 20b, and the heat insulating tube 100 is pressed against the elastic body 30b to be connected in a compressed state, whereby the foamed resin layer 110 of the heat insulating tube 100 is connected by the elastic body 30b. Infiltration of water into the water is suppressed.

(Production method)
Examples of the method for manufacturing a pipe joint include a method having the following steps (a) to (b).
(A) The tube main body 10, the receiving portion 20a, and the receiving portion 20b are molded.
(B) The elastic body 30a and the elastic body 30b are produced, and the elastic body 30a is adhered to the receiving surface 25a, and the elastic body 30b is adhered to the receiving surface 25b.

The molding method of the tube main body portion 10, the receiving portion 20a and the receiving portion 20b in the step (a) is not particularly limited, and for example, the injection molding method described in Japanese Patent No. 36999579 can be used. Specifically, for example, the non-foamable resin composition forming the non-foaming resin layer 50 is injected into a mold having a cavity forming the tube main body portion 10, the receiving portion 20a and the receiving portion 20b. Fill halfway. Next, the foamable resin composition forming the foamed resin layer 40 is injected, and the foamable resin composition is inserted into the inside of the non-foamable resin composition by utilizing the injection pressure and the foaming pressure of the foamable resin composition. Fill the cavity tightly with them. Next, it is cooled and solidified to obtain an integral product in which the tube main body 10, the receiving portion 20a, and the receiving portion 20b are integrated, in which the foamed resin layer 40 is covered with the non-foamed resin layer 50.

Examples of the step (b) include the following two types of steps.
(B-1) After providing an adhesive layer on one surface of the elastic sheet, they are punched out in an annular shape to form an annular elastic body having an adhesive layer, and the elastic body is bonded to the receiving surface via the adhesive layer. ..
(B-2) After providing an adhesive layer on the receiving surface, the elastic body is adhered to the receiving surface via the adhesive layer.

In the step (b-1), for example, an adhesive is applied to one surface of an elastic sheet manufactured by extrusion molding or the like using a resin material constituting an elastic body to provide an adhesive layer. The method of applying the adhesive to the elastic sheet is not particularly limited, and examples thereof include a roll coater and a die coater. Further, a double-sided tape may be attached to one surface of the elastic sheet to provide an adhesive layer.
As the elastic sheet, a foamed sheet may be produced by using a foamable resin composition.

Next, the laminated sheet provided with the adhesive layer on one surface of the elastic sheet is punched out in an annular shape to obtain a laminated body of the adhesive layer 26a and the elastic body 30a. Next, the adhesive layer 26a is inserted into the receiving portion 20a on the receiving surface 25a side, and the elastic body 30a is adhered to the receiving surface 25a via the adhesive layer 26a. Similarly, after the laminated sheet is punched out in an annular shape to obtain a laminated body of the adhesive layer 26b and the elastic body 30b, the elastic body 30b is received and adhered to the receiving surface 25b via the adhesive layer 26b.

In the step (b-2), for example, an adhesive is applied to the receiving surface 25a, or a double-sided tape is attached to provide the adhesive layer 26a. Next, the elastic body 30a is inserted into the receiving portion 20a, and the elastic body 30a is adhered to the receiving surface 25a via the adhesive layer 26a. Similarly, an adhesive is applied to the receiving surface 25b or a double-sided tape is attached to provide the adhesive layer 26b, and then the elastic body 30b is adhered to the receiving surface 25b via the adhesive layer 26b.
The elastic body 30a and the elastic body 30b can be obtained, for example, by punching an elastic sheet in an annular shape.

[Second Embodiment]
The fitting according to the embodiment of the present invention may be a three-way branched T-shaped fitting generally referred to as "cheese". Specifically, for example, the pipe joint 2 illustrated in FIG. 5 may be used.
The pipe joint 2 includes a pipe main body 210, three receiving portions 220a to 220c, and three elastic bodies 230a to 230c.

The pipe body 210 has a flow path branched in three directions inside, and three openings 212a to 212c are formed. The linear first pipe shaft O1 from the opening 212a to the opening 212b and the linear second pipe shaft O2 from the opening 212c to the center of the pipe body 210 are 90.0 ° to ~. It intersects at an angle of 91.1 °.

The three receiving portions 220a to 220c are provided so as to surround the three openings 212a to 212c of the pipe main body portion 210, respectively. In the pipe body 210, an injection gate portion 214 is provided at a position facing the opening 212c with the first pipe shaft O1 in between, which is a position to be injected at the time of molding.

At the boundary between the receiving portion 220a and the opening 212a of the pipe main body 210, an annular step 224a protruding inward from the inner surface 221a of the receiving portion 220a is formed. The surface of the step 224a facing the opening end 223a of the receiving portion 220a is a receiving surface 225a for receiving the pipe inserted into the receiving portion 220a, a so-called stopper.

Similarly, an annular step 224b is formed at the boundary between the receiving portion 220b and the opening portion 212b of the pipe main body portion 210, and the surface facing the opening end 223b is the receiving surface 225b. Further, an annular step 224c is formed at the boundary portion between the receiving portion 220c and the opening portion 212c of the pipe main body portion 210, and the surface facing the opening end 223c is the receiving surface 225c.

The tube main body 210 includes a foamed resin layer (heat insulating layer) 240 and a non-foamed resin layer 250. The inner and outer surfaces of the foamed resin layer 240 are covered with the non-foamed resin layer 250. The receiving portion 220a, the receiving portion 220b, and the receiving portion 220c are formed of a non-foamed resin layer 250.

The elastic bodies 230a to 230c are annular elastic bodies. The elastic body 230a is adhered to the receiving surface 225a in the receiving portion 220a via the adhesive layer 226a. The elastic body 230b is adhered to the receiving surface 225b in the receiving portion 220b via the adhesive layer 226b. The elastic body 230c is adhered to the receiving surface 225b in the receiving portion 220b via the adhesive layer 226b.

The front view shape of the elastic bodies 230a to 230c is preferably similar to the ring shape of the receiving surfaces 225a to 225c in the front view, and an annular shape is preferable. The front view shape of the elastic bodies 230a to 230c may be different from the front view shape of the receiving surfaces 225a to 225c, and may be an ellipse, a polygon, or the like.

In the present embodiment, the elastic bodies 230a to 230c have a rectangular cross section in the thickness direction, and the adhesive layers 226a to 226c are provided only on the surfaces of the elastic bodies 230a to 230c facing the receiving surfaces 225a to 225c. Has been done. The shape of the cross section of the elastic bodies 230a to 230c in the thickness direction is not limited to a rectangular shape, and may be a circular shape, an elliptical shape, a polygonal shape, or the like.

The preferable range of the thickness of the elastic bodies 230a to 230c is the same as the preferable range of the thickness of the elastic body 30a.
The outer diameter of the elastic body 230a is equal to or less than the inner diameter of the receiving portion 220a. Similarly, the outer diameter of the elastic body 230b is equal to or less than the inner diameter of the receiving portion 220b. The outer diameter of the elastic body 230c is equal to or less than the inner diameter of the receiving portion 220c. As a result, when the elastic bodies 230a to 230c are adhered to the receiving surfaces 225a to 225c, the adhesive may adhere to an unexpected portion in the receiving portions 220a to 220c, or the elastic bodies 230a to 230c may bend. It is possible to suppress the displacement of the adhesive positions of the elastic bodies 230a to 230c.

Difference between the inner diameter of the receiving portion 220a and the outer diameter of the elastic body 230a, the difference between the inner diameter of the receiving portion 220b and the outer diameter of the elastic body 230b, the difference between the inner diameter of the receiving portion 220c and the outer diameter of the elastic body 230c The preferred range of is the same as the preferred range of the difference d1-d2. These differences may be the same or different from each other.

The inner diameter of the elastic body 230a is preferably equal to or larger than the inner diameter of the step 224a. Similarly, the inner diameter of the elastic body 230b is preferably equal to or larger than the inner diameter of the step 224b. The inner diameter of the elastic body 230c is preferably equal to or larger than the inner diameter of the step 224c.

The preferred range of the difference between the inner diameter of the elastic body 230a and the inner diameter of the step 224a, the difference between the inner diameter of the elastic body 230b and the inner diameter of the step 224b, and the difference between the inner diameter of the elastic body 230c and the inner diameter of the step 224c is the difference d3-d4. It is the same as the preferable range of. These differences may be the same or different from each other.

The peel strength of the receiving surface 225a and the elastic body 230a, the peel strength of the receiving surface 225b and the elastic body 230b, and the peel strength of the receiving surface 225c and the elastic body 230c are 1N / 25 mm or more. The preferable range of these peel strengths is the same as the preferable range of the peel strengths of the receiving surface 25a and the elastic body 30a.

The preferable range of the thickness of the adhesive layers 226a and 226b is the same as the preferable range of the thickness of the adhesive layer 26a.

In the pipe joint 2, the three heat insulating pipes 100 can be inserted into the receiving portions 220a to 220c, respectively, and the heat insulating pipe 100 can be connected by pressing against the elastic bodies 230a to 230c in a compressed state. As a result, the elastic bodies 230a to 230c prevent water from entering the foamed resin layer 110 of the heat insulating pipe 100.

The pipe joint 2 can be manufactured in the same manner as the pipe joint 1. For example, the pipe body 210 and the sockets 220a to 220c are integrally molded by injection molding similar to the method described in the pipe joint 1. Next, after providing an adhesive layer on one surface of the elastic sheet, they are punched out in an annular shape to form an annular elastic body 230a to 230c having an adhesive layer 260a to 260c, and the elastic body is formed via the adhesive layer 260a to 260c. The 230a to 230c are adhered to the receiving surfaces 225a to 225c. Alternatively, after the adhesive layers 226a to 226c are provided on the receiving surfaces 225a to 225c, the elastic bodies 230a to 230c are adhered to the receiving surfaces 225a to 225c via the adhesive layers 226a to 226c.

As described above, in the present invention, an elastic body having an outer diameter equal to or less than the inner diameter of the receiving portion is adhered to the receiving surface of the step via the adhesive layer. This facilitates the adhesion of the elastic body to the receiving surface in the receiving portion. In addition, when the elastic body is adhered to the receiving surface in the receiving portion, the adhesive may adhere to an unexpected part in the receiving portion, or the elastic body may come into contact with the inner peripheral surface of the receiving portion and bend. Is suppressed, so that the adhesive position of the elastic body does not easily shift. Further, the peel strength of the receiving surface and the elastic body is set to 1 N / 25 mm or more. As a result, peeling of the elastic body due to vibration or impact during transportation, contraction of the connected heat insulating pipe, or the like is suppressed. From these facts, the effect of suppressing the infiltration of water into the foamed resin layer of the heat insulating tube by the elastic body is sufficiently exhibited.

The pipe joint of the present invention is not limited to the pipe joints 1 and 2 described above, and can be appropriately changed as long as the purpose is not deviated. For example, the pipe joint of the present invention may be a straight tubular one, a reducer whose inner diameter gradually decreases from the opening at one end to the opening at the other end, a pipe joint with a valve, or the like.
Further, in the embodiment of the present invention, it is said that the composition is composed of a foamable resin composition and a non-foamable resin composition, but the present invention is not limited to this. For example, the receiving portion and the pipe main body are composed only of the non-foamable resin composition, and the pipe main body 10 covers the inner pipe portion integrally formed with the receiving portion and the outer side of the inner pipe portion. A pipe joint may be provided with a pipe portion and a hollow layer as a heat insulating layer is formed by separating the outer surface of the inner pipe portion and the inner surface of the outer pipe portion.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following description.

[Example 1]
The pipe joint 1 illustrated in FIGS. 1 to 4 was manufactured.
Specifically, a foamable resin composition in which azodicarbonamide was added as a foaming agent to ABS resin and kneaded, and a non-foamable resin composition in which ABS resin and polymethylmethacrylate were kneaded were prepared. A pipe body 10, a receiving portion 20a, and a receiver having a foamed resin layer 40 formed of the foamable resin composition and a non-foamed resin layer 50 formed of the non-foamable resin composition by injection molding. An integral part of the mouth portion 20b was molded. The inner diameters d1 of the receiving portions 20a and 20b were 88.65 mm, and the inner diameters d4 of the steps 24a and 24b were 69 mm.
A liquid pressure-sensitive adhesive (solvent component: ethyl acetate, 20) containing an acrylic acid alkyl ester-based copolymer as a pressure-sensitive adhesive component on one surface of an elastic sheet (material: foamed polyethylene, foaming ratio: 30 times, thickness: 6 mm). A viscosity of 5000 mPa · s) at ° C. was applied so as to be 50 g / m ^2, and punched out in an annular shape to obtain a laminated body of an elastic body 30a having a rectangular cross section and an adhesive layer 26a. In the same manner, a laminate of the elastic body 30b and the adhesive layer 26b was obtained. The outer diameters d2 of the elastic bodies 30a and 30b were 88 mm, and the inner diameter d3 was 69 mm. d1-d2 was 0.65 mm and d3-d4 was 0 mm.
The laminated body of the elastic body 30a and the adhesive layer 26a was inserted into the receiving portion 20a so that the adhesive layer 26a faced the step 24a side, and the elastic body 30a was adhered to the receiving surface 25a via the adhesive layer 26a. Similarly, the laminated body of the elastic body 30b and the adhesive layer 26b was inserted into the receiving portion 20b, and the elastic body 30b was adhered to the receiving surface 25b via the adhesive layer 26b. It was stored at 25 ° C. for 168 hours and aged to obtain a pipe joint 1.

[Example 2]
The pipe joint 1 used was the same as that manufactured in Example 1.
Using the same elastic sheet as in Example 1, elastic bodies 30a and 30b were obtained by punching in an annular shape. The outer diameter d2 of the elastic bodies 30a and 30b was 86 mm, and the inner diameter d3 was 71 mm. d1-d2 was 2 mm and d3-d4 was 1 mm.
An annular double-sided tape (thickness 0.2 mm) having the same shape as the elastic bodies 30a and 30b is attached to the receiving surfaces 25a and 25b of the steps 24a and 24b to form the adhesive layers 26a and 26b, and then the adhesive layers 26a and 26a, The elastic bodies 30a and 30b were adhered to the receiving surfaces 25a and 25b via the 26b. It was stored at 25 ° C. for 48 hours and aged to obtain a pipe joint 1.

[Example 3]
After applying the adhesive layer to the receiving surface 25a, the elastic body 30a (material: foamed polyethylene, foaming ratio: 20 times, thickness: 8 mm) is adhered, and then the adhesive layer is applied to the receiving surface 25b and then the elastic body. A pipe joint was manufactured by the same method as in Example 1 except that an elastic body 30b made of the same material and thickness as 30a was adhered.

[Comparative Example 1]
A pipe joint was manufactured by the same method as in Example 1 except that the outer diameters d2 of the elastic bodies 30a and 30b were 89 mm.

[Comparative Example 2]
The same as in Example 1 except that the outer diameters d2 of the elastic bodies 30a and 30b are 90 mm and the adhesive layer is also formed on the entire surface of the side surface of the elastic body (the surface facing the inner surface of the receiving portions 20a and 20b). The pipe fitting was manufactured by the method.

[Comparative Example 3]
Example 1 except that a liquid pressure-sensitive adhesive containing an acrylic acid alkyl ester-based copolymer as a pressure-sensitive adhesive component (solvent component: ethyl acetate, viscosity at 20 ° C. of 5000 mPa · s) was applied so as to be 3 g / m ^2. The pipe joint was manufactured by the same method as above.

[Peel strength]
The socket portion is cut perpendicularly in the axial direction along the surface of the elastic body on the opening end side (cutting position X in FIG. 3), and the pipe body portion is cut vertically in the axial direction so as to include a step (cutting position X in FIG. 3). At the cutting position Y) in FIG. 3, an annular cut piece having an exposed surface of the elastic body was obtained. With the surface of the elastic body of the cut piece viewed from the front, the cut piece was divided into four equal parts at equal angles (90 degrees each) around the central axis to prepare a measurement sample. A non-foamed resin layer with a step was cut at the peripheral end of the measurement sample to expose the adhesive surface of the elastic body. The exposed part of the elastic body at the end of the measurement sample is grasped with a jig, and under the conditions of 23 ° C., 65% RH, peeling angle 180 degrees, and tensile speed 300 mm / min, a tensile tester is used via a load cell. The jig was pulled to perform a peeling test of the measurement sample three times.
The average value of the measured peel strength recorded in the load cell was divided by the width (mm) of the elastic body of the measurement sample and multiplied by 25 to convert it into a value having a width of 25 mm to obtain the peel strength.

[Easy to attach elastic body]
The ease of sticking the elastic body was evaluated according to the following evaluation criteria.
〇: There was no deviation in the adhesive position of the elastic body.
X: The adhesive position of the elastic body was displaced.

1, 2, ... Pipe fittings, 10, 210 ... Pipe body, 12a, 12b, 212a to 212c ... Opening, 20a, 20b, 220a to 220c ... Receptacle, 21a, 21b ... Opening end, 24a, 24b, 224a ~ 224c ... Step, 25a, 25b, 225a ~ 225c ... Receiving surface, 26a, 26b, 226a ~ 226c ... Adhesive layer, 30a, 30b, 230a ~ 230c ... Elastic body, 40, 240 ... Foamed resin layer, 50, 250 ... Non-foamed resin layer.

Claims (6)

A pipe joint including a pipe body portion provided with a heat insulating layer, a tubular receiving portion surrounding an opening of the pipe body portion, and an annular elastic body.
An annular step protruding inward from the inner surface of the receiving portion is formed at the boundary portion between the receiving portion and the pipe main body portion.
The surface of the step facing the opening end of the receiving portion is a receiving surface for receiving the pipe inserted into the receiving portion.
The outer diameter of the elastic body is equal to or less than the inner diameter of the socket.
The elastic body is adhered to the receiving surface via an adhesive layer,
A pipe joint in which the peel strength between the receiving surface and the elastic body is 1 N / 25 mm or more. The pipe joint according to claim 1, wherein the inner diameter of the elastic body is equal to or larger than the inner diameter of the step. The pipe joint according to claim 1 or 2, wherein the thickness of the elastic body is 2 mm or more and 15 mm or less. The shape of the cross section of the elastic body in the thickness direction is rectangular.
The pipe joint according to any one of claims 1 to 3, wherein the adhesive layer is provided only on the surface of the elastic body facing the receiving surface. The method for manufacturing a pipe joint according to any one of claims 1 to 4.
After providing an adhesive layer on one surface of the elastic sheet, they are punched out in an annular shape to form the annular elastic body having the adhesive layer, and the elastic body is adhered to the receiving surface via the adhesive layer. , Manufacturing method of pipe joints. The method for manufacturing a pipe joint according to any one of claims 1 to 4.
A method for manufacturing a pipe joint, in which the adhesive layer is provided on the receiving surface, and then the elastic body is adhered to the receiving surface via the adhesive layer.

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